Marinus Link

Project Overview

The Marinus Link project represents one of Australia’s most ambitious energy infrastructure developments – a proposed 1,500 MW undersea and underground electricity interconnector between Tasmania and Victoria. Once complete, it will enable bi-directional flow of renewable energy across the National Electricity Market (NEM) and underpin Hydro Tasmania’s “Battery of the Nation” initiative.

The project reached financial close for Stage 1 in 2025, marking a major milestone in Australia’s transition toward a cleaner and more resilient energy future. Given the project’s scale, technical complexity, and cross-jurisdictional coordination requirements, independent project controls assurance was critical to support investor, regulatory, and parliamentary approval processes.

Since 2023, TBH partnered with Marinus Link Pty Ltd to provide specialist time, cost and risk management services, helping to develop credible, evidence-based delivery plans that have underpinned key governance and funding decisions leading up to financial close.

TBH’s Role

TBH was engaged by Marinus Link to provide integrated project controls expertise encompassing cost estimation, schedule development and quantitative risk analysis across multiple project phases and packages. The objective was to ensure alignment and confidence across the project’s planning, regulatory and financial processes.

Cost Estimation and Review

• Conducted a peer review of the Victorian Land Cable Route Cost Estimate, assessing the completeness, constructability and risk allowances of the initial design-stage cost plan.
• Provided enhanced scope definition and constructability input, identifying potential constraints and developing refined cost models that improved estimate accuracy and defensibility.
• Subsequently engaged to prepare further cost plans for both civil works and converter station packages, including complex components such as contaminated ground remediation and logistics.
• Aligned cost breakdown structures (CBS) with project Work Breakdown Structures (WBS) to ensure traceability between design, cost and schedule data.

Integrated Master Schedule Development

• Developed an Integrated Master Schedule (IMS) covering land cable, converter stations and subsea cable installation to establish a unified view of project delivery.
• Ensured alignment between cost, risk and time dependencies across multiple contractors and geographic locations (Tasmania and Victoria).
• Modelled key interfaces, including environmental approvals, access and commissioning windows, to support a realistic and deliverable program.

Quantitative Risk Analysis (QRA)

• Delivered integrated Quantitative Schedule and Cost Risk Analyses (QSRA/QCRA), incorporating Monte Carlo simulations to quantify uncertainty across all project components.
• Linked risk drivers to delivery strategy, environmental conditions and regulatory dependencies to assess potential impacts on cost and time.
• Conducted scenario modelling to test alternative delivery and commercial strategies, ensuring risk-informed decision-making for governance and investment approval.

Regulatory and Governance Assurance Support

• • Produced risk-adjusted cost and schedule outputs that directly informed investment submissions to Infrastructure Australia, Energy Security Board and other regulatory stakeholders.
  • Supported multiple rounds of external assurance and review, providing the evidence base needed for financial close and confidence in delivery feasibility.

TBH Difference

TBH’s integrated approach to time, cost and risk was fundamental to building regulator and financier confidence in Marinus Link’s delivery strategy. TBH’s alignment of cost, schedule and risk data – provided a clear, defensible line of sight between assumptions, contingency and delivery outcomes, enabling consistent, integrated project controls that reflected real-world delivery conditions. Early peer review improved cost realism and schedule credibility, ensuring the delivery plan reflected true construction sequencing and constraints. TBH’s quantitative analysis directly informed governance bodies and financiers, demonstrating that the project’s baseline was achievable and well understood. Drawing on decades of experience in energy, transmission and infrastructure megaprojects, TBH provided Marinus Link with confidence grounded in proven methodology and best practice. Through these contributions, TBH helped Marinus Link navigate critical milestones from concept validation to financial close – enabling Australia’s next step toward a renewable, interconnected energy future.